Sharrows in San Francisco

In 2004, the city of San Francisco paid Alta Planning & Design to conduct a study on the use of sharrows in the city.  (For those of you unfamiliar, this is a sharrow:)

 

 

The city was having high incidents of 'dooring', as well as cyclists riding on sidewalks, against traffic, and motorists demonstrating aggressive behavior.  The goal of the study was to determine which markings were most effective, and how they should be used.  The really neat part of this study is how it was conducted.  The group used before-and-after video footage to determine the effectiveness of the sharrow.  They tested two versions of the sharrow; the 'Chevron style' shown above and the 'Bike-In-House'  version here:

 

They looked for cyclist positions relative to the curb or a parked car, as well as passing motorist traffic positions relative to the cyclist.  In short, what they determined is that ANY sharrow improves cyclist and motorist positioning.  Sharrows created a buffer between cyclists and parked cars, as well as between the passing cars and cyclists.  They did a good job of evaluating variables, and in the end concluded that sharrows can be an effective solution to improve cyclist safety and both cyclist and motorist behavior.

I really like Sharrows, for a number of reasons. I think they do convey to motorists that cyclists have a right to lane, and a right to be on the road.  They also create a 'mental space' that helps drivers provide a buffer to cyclists that they may not otherwise give.  They are much more cost effective than full-on bike lanes as well.  I think bike lanes can be useful, but in my opinion they convey a sense that 'bikes belong in bike lanes' and in Denver and the surrounding areas, there simply aren't enough bike lanes for that to be realistic.

The complete study can be found here:

http://www.sfmta.com/cms/uploadedfiles/dpt/bike/Bike_Plan/Shared%20Lane%20Marking%20Full%20Report-052404.pdfhttp://www.sfmta.com/cms/uploadedfiles/dpt/bike/Bike_Plan/Shared%20Lane%20Marking%20Full%20Report-052404.pdf

The study isn't terribly long (26 pages) and is definitely worth reading!